What the heck are cilia and flagella and how did they get into my science class?

Cilia and flagella are projections from the cell. They look like tiny hairs. They are made up of microtubules. They are designed either to move the cell itself or to move substances over or around the cell. In this regard, they are a lot like the legs and arms of humans.

What the heck are cilia and flagella and how did they get into my science class?